An auto website says Volkswagen is planning a major expansion for its Chattanooga plant that could add production space for a new Volkswagen crossover and ultimately for Audi and Porsche sport utility vehicles.

The site Automobile cited unnamed sources as saying that VW officials are almost ready to sign off on a second phase that would increase the plant's output by 180,000 to 200,000 units a year.

It said the plan is to let all three brands participate in the new venture. The plant is expected to start production soon on a new, made-for-America midsize sedan.